Nonvolatile memories using resistance materials include phase-change random access memories (PRAMs), resistive RAMs (RRAMs), and magnetic RAMs (MRAMs). While dynamic RAMs (DRAMs) or flash memories store data using charge, nonvolatile memories using resistance materials store data using a state change of a phase-change material, such as chalcogenide alloy (in the case of PRAMs), a resistance change of a variable resistance material (in the case of RRAMs), or a resistance change of a magnetic tunnel junction (MTJ) thin film according to a magnetization state of a ferromagnetic material (in the case of MRAMs).
Semiconductor products may need to process high capacity data while they are gradually becoming more compact. Accordingly, there is demand for increasing the operating speed and integration level of memory devices used in such semiconductor products. To meet such demand, there have been proposed magnetic memory devices implementing memory functions using a resistance change depending on a change in the polarity of a magnetic material, and various studies of the magnetic memory devices are being conducted.